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[209.132.180.67]) by mx.google.com with ESMTP id t28si9100308pfe.145.2019.05.10.13.56.12; Fri, 10 May 2019 13:56:31 -0700 (PDT) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=pass header.i=@google.com header.s=20161025 header.b=evlcGdIs; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=REJECT sp=REJECT dis=NONE) header.from=google.com Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728051AbfEJUya (ORCPT + 99 others); Fri, 10 May 2019 16:54:30 -0400 Received: from mail-oi1-f194.google.com ([209.85.167.194]:39081 "EHLO mail-oi1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728027AbfEJUy3 (ORCPT ); Fri, 10 May 2019 16:54:29 -0400 Received: by mail-oi1-f194.google.com with SMTP id v2so2080770oie.6 for ; Fri, 10 May 2019 13:54:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=wT/cEmU9OzhSA7tBC6sHp/9lnFjqpmjhDQ7p3B9EpFU=; b=evlcGdIsJdYGFkgmf7g49h2klNY0YDgLam0NSxBlsjnIvCyifza0rgc7Kq0J5qmAdA hd0xvzMMOFTjDkUqtbp9Csqd/JIB4Q/9pyDFXYsatysjFYSayOB6R/17rqPL3dsDFKbu CpB1t/Y5N1NsJdrqQqSqw8dZUeUluYMIMdDGCs+6m3ley31zma2gSaxhU1ecliKiQuHb STHQGjDC5w8qxg8OQKDXhctVTJVc43Ml5hH1/yZ8PBYWnwVLGMbfwFwUGqvcrrN1U/Nb /FIgrQ/F3IDvmmebdaC68E2dZKT6zjcG9rqNRGXkw9XZeR6dne5aQ/sOdhecRUXr+TGP otBQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=wT/cEmU9OzhSA7tBC6sHp/9lnFjqpmjhDQ7p3B9EpFU=; b=k8NQOwBMTvnmtI2nNY9AYE5VtENlPn/njgg7SXK5SXGAGUEBNdKY0f7pY/o4jYOl5i M3LWAIwLilTH0/c1Ax8YeSiMwU9mg7BBqWOUvwOppO+8MCqTiUBFefQQ7zP77L5JZfTj HmRzJROWmVuLPstBVKteUya8UeuOg1UO5fepqh5Nv4m8NVam4q4Q2Be2bbvmTZBmyHCj ak0xfb0aqN+9xmzRMmaY63wnhbssJYcYcvCeENDVhzJVXW1Nmq05N9wleUi5DZn9O6ee wT8ISLDeRMqMv8G7i39xPDN3SwvYqLB8haObWF5mUs4A4wrEktAhmzM41M1CKIqOaT0G xaRw== X-Gm-Message-State: APjAAAWAYDw+Ifva1gIRXRgIz/Ndi2enWRK3Al1cVhZSnL0Ba7Ozw63Q Rz1YuDe4x6B5RkwTbk2VD3uNE8v9s9/zWFiunjGORQ== X-Received: by 2002:aca:4586:: with SMTP id s128mr6126273oia.148.1557521668652; Fri, 10 May 2019 13:54:28 -0700 (PDT) MIME-Version: 1.0 References: <20190509015856.GB7031@mit.edu> <580e092f-fa4e-eedc-9e9a-a57dd085f0a6@gmail.com> <20190509032017.GA29703@mit.edu> <7fd35df81c06f6eb319223a22e7b93f29926edb9.camel@oracle.com> <20190509133551.GD29703@mit.edu> <875c546d-9713-bb59-47e4-77a1d2c69a6d@gmail.com> <20190509214233.GA20877@mit.edu> <20190509233043.GC20877@mit.edu> <8914afef-1e66-e6e3-f891-5855768d3018@deltatee.com> <6d6e91ec-33d3-830b-4895-4d7a20ba7d45@gmail.com> <1781164863be8d21a7e1890ae6dfee9be101d0a0.camel@oracle.com> In-Reply-To: <1781164863be8d21a7e1890ae6dfee9be101d0a0.camel@oracle.com> From: Brendan Higgins Date: Fri, 10 May 2019 13:54:16 -0700 Message-ID: Subject: Re: [PATCH v2 00/17] kunit: introduce KUnit, the Linux kernel unit testing framework To: Knut Omang Cc: Daniel Vetter , Frank Rowand , Logan Gunthorpe , "Theodore Ts'o" , "Bird, Timothy" , Greg KH , Kees Cook , Kieran Bingham , "Luis R. Rodriguez" , Rob Herring , Stephen Boyd , Shuah Khan , devicetree , dri-devel , kunit-dev@googlegroups.com, Linux Doc Mailing List , linux-fsdevel@vger.kernel.org, linux-kbuild , Linux Kernel Mailing List , "open list:KERNEL SELFTEST FRAMEWORK" , linux-nvdimm , linux-um@lists.infradead.org, Sasha Levin , Amir Goldstein , Dan Carpenter , Dan Williams , Jeff Dike , Joel Stanley , Julia Lawall , Kevin Hilman , Michael Ellerman , Petr Mladek , Richard Weinberger , David Rientjes , Steven Rostedt , wfg@linux.intel.com Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 10, 2019 at 5:13 AM Knut Omang wrote: > On Fri, 2019-05-10 at 03:23 -0700, Brendan Higgins wrote: > > > On Fri, May 10, 2019 at 7:49 AM Knut Omang wrote: > > > > > > > > On Thu, 2019-05-09 at 22:18 -0700, Frank Rowand wrote: > > > > > On 5/9/19 4:40 PM, Logan Gunthorpe wrote: > > > > > > > > > > > > > > > > > > On 2019-05-09 5:30 p.m., Theodore Ts'o wrote: > > > > > >> On Thu, May 09, 2019 at 04:20:05PM -0600, Logan Gunthorpe wrote: > > > > > >>> > > > > > >>> The second item, arguably, does have significant overlap with kselftest. > > > > > >>> Whether you are running short tests in a light weight UML environment or > > > > > >>> higher level tests in an heavier VM the two could be using the same > > > > > >>> framework for writing or defining in-kernel tests. It *may* also be valuable > > > > > >>> for some people to be able to run all the UML tests in the heavy VM > > > > > >>> environment along side other higher level tests. > > > > > >>> > > > > > >>> Looking at the selftests tree in the repo, we already have similar items to > > > > > >>> what Kunit is adding as I described in point (2) above. kselftest_harness.h > > > > > >>> contains macros like EXPECT_* and ASSERT_* with very similar intentions to > > > > > >>> the new KUNIT_EXECPT_* and KUNIT_ASSERT_* macros. > > > > > >>> > > > > > >>> However, the number of users of this harness appears to be quite small. Most > > > > > >>> of the code in the selftests tree seems to be a random mismash of scripts > > > > > >>> and userspace code so it's not hard to see it as something completely > > > > > >>> different from the new Kunit: > > > > > >>> > > > > > >>> $ git grep --files-with-matches kselftest_harness.h * > > > > > >> > > > > > >> To the extent that we can unify how tests are written, I agree that > > > > > >> this would be a good thing. However, you should note that > > > > > >> kselftest_harness.h is currently assums that it will be included in > > > > > >> userspace programs. This is most obviously seen if you look closely > > > > > >> at the functions defined in the header files which makes calls to > > > > > >> fork(), abort() and fprintf(). > > > > > > > > > > > > Ah, yes. I obviously did not dig deep enough. Using kunit for > > > > > > in-kernel tests and kselftest_harness for userspace tests seems like > > > > > > a sensible line to draw to me. Trying to unify kernel and userspace > > > > > > here sounds like it could be difficult so it's probably not worth > > > > > > forcing the issue unless someone wants to do some really fancy work > > > > > > to get it done. > > > > > > > > > > > > Based on some of the other commenters, I was under the impression > > > > > > that kselftests had in-kernel tests but I'm not sure where or if they > > > > > > exist. > > > > > > > > > > YES, kselftest has in-kernel tests. (Excuse the shouting...) > > > > > > > > > > Here is a likely list of them in the kernel source tree: > > > > > > > > > > $ grep module_init lib/test_*.c > > > > > lib/test_bitfield.c:module_init(test_bitfields) > > > > > lib/test_bitmap.c:module_init(test_bitmap_init); > > > > > lib/test_bpf.c:module_init(test_bpf_init); > > > > > lib/test_debug_virtual.c:module_init(test_debug_virtual_init); > > > > > lib/test_firmware.c:module_init(test_firmware_init); > > > > > lib/test_hash.c:module_init(test_hash_init); /* Does everything */ > > > > > lib/test_hexdump.c:module_init(test_hexdump_init); > > > > > lib/test_ida.c:module_init(ida_checks); > > > > > lib/test_kasan.c:module_init(kmalloc_tests_init); > > > > > lib/test_list_sort.c:module_init(list_sort_test); > > > > > lib/test_memcat_p.c:module_init(test_memcat_p_init); > > > > > lib/test_module.c:static int __init test_module_init(void) > > > > > lib/test_module.c:module_init(test_module_init); > > > > > lib/test_objagg.c:module_init(test_objagg_init); > > > > > lib/test_overflow.c:static int __init test_module_init(void) > > > > > lib/test_overflow.c:module_init(test_module_init); > > > > > lib/test_parman.c:module_init(test_parman_init); > > > > > lib/test_printf.c:module_init(test_printf_init); > > > > > lib/test_rhashtable.c:module_init(test_rht_init); > > > > > lib/test_siphash.c:module_init(siphash_test_init); > > > > > lib/test_sort.c:module_init(test_sort_init); > > > > > lib/test_stackinit.c:module_init(test_stackinit_init); > > > > > lib/test_static_key_base.c:module_init(test_static_key_base_init); > > > > > lib/test_static_keys.c:module_init(test_static_key_init); > > > > > lib/test_string.c:module_init(string_selftest_init); > > > > > lib/test_ubsan.c:module_init(test_ubsan_init); > > > > > lib/test_user_copy.c:module_init(test_user_copy_init); > > > > > lib/test_uuid.c:module_init(test_uuid_init); > > > > > lib/test_vmalloc.c:module_init(vmalloc_test_init) > > > > > lib/test_xarray.c:module_init(xarray_checks); > > > > > > > > > > > > > > > > If they do exists, it seems like it would make sense to > > > > > > convert those to kunit and have Kunit tests run-able in a VM or > > > > > > baremetal instance. > > > > > > > > > > They already run in a VM. > > > > > > > > > > They already run on bare metal. > > > > > > > > > > They already run in UML. > > > > > > > > > > This is not to say that KUnit does not make sense. But I'm still trying > > > > > to get a better description of the KUnit features (and there are > > > > > some). > > > > > > > > FYI, I have a master student who looks at converting some of these to KTF, such as > > for > > > > instance the XArray tests, which lended themselves quite good to a semi-automated > > > > conversion. > > > > > > > > The result is also a somewhat more compact code as well as the flexibility > > > > provided by the Googletest executor and the KTF frameworks, such as running selected > > > > tests, output formatting, debugging features etc. > > > > > > So is KTF already in upstream? Or is the plan to unify the KTF and > > > > I am not certain about KTF's upstream plans, but I assume that Knut > > would have CC'ed me on the thread if he had started working on it. > > You are on the Github watcher list for KTF? Yep! I have been since LPC in 2017. > Quite a few of the commits there are preparatory for a forthcoming kernel patch set. > I'll of course CC: you on the patch set when we send it to the list. Awesome! I appreciate it. > > > > Kunit in-kernel test harnesses? Because there's tons of these > > > > No, no plan. Knut and I talked about this a good while ago and it > > seemed that we had pretty fundamentally different approaches both in > > terms of implementation and end goal. Combining them seemed pretty > > infeasible, at least from a technical perspective. Anyway, I am sure > > Knut would like to give him perspective on the matter and I don't want > > to say too much without first giving him a chance to chime in on the > > matter. > > I need more time to study KUnit details to say, but from a 10k feet perspective: > I think at least there's a potential for some API unification, in using the same macro > names. How about removing the KUNIT_ prefix to the test macros ;-) ? Heh, heh. That's actually the way I had it in the earliest versions of KUnit! But that was pretty much the very first thing everyone complained about. I think I went from no prefix (like you are suggesting) to TEST_* before the first version of the RFC at the request of several people I was kicking the idea around with, and then I think I was asked to go from TEST_* to KUNIT_* in the very first revision of the RFC. In short, I am sympathetic to your suggestion, but I think that is non-negotiable at this point. The community has a clear policy in place on the matter, and at this point I would really prefer not to change all the symbol names again. > That would make the names shorter, saving typing when writing tests, and storage ;-) > and also make the names more similar to KTF's, and those of user land unit test You mean the Googletest/Googlemock expectations/assertions? It's a great library (with not so great a name), but unfortunately it is written in C++, which I think pretty much counts it out here. > frameworks? Also it will make it possible to have functions compiling both with KTF and > KUnit, facilitating moving code between the two. I think that would be cool, but again, I don't think this will be possible with Googletest/Googlemock. > > Also the string stream facilities of KUnit looks interesting to share. I am glad you think so! If your biggest concern on my side is test macro names (which I think is a no-go as I mentioned above), I think we should be in pretty good shape once you are ready to move forward. Besides, I have a lot more KUnit patches coming after this: landing this patchset is just the beginning. So how about we keep moving forward on this patchset?